Lose your luggage for two days and you find out how little you actually need.

Need is mostly a habit that has never been tested. Stripped down to what fits in your pockets, you find that much of what you carry is there because you own it, not because it does anything. Two days without it is uncomfortable for about an hour and then unremarkable. The list of genuine requirements is embarrassingly short.

Run a mild version on purpose. Pack for a weekend in one small bag, or box up a third of your room for a month and see what you go looking for. Whatever you never went looking for can go.